


Trade

by FullOfBoredom



Category: Undertale (Video Game)
Genre: Implied/Referenced Self-Harm, M/M, Nightkiller - Freeform, killermare - Freeform
Language: English
Status: In-Progress
Published: 2021-02-07
Updated: 2021-02-07
Packaged: 2021-03-12 07:55:36
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence
Chapters: 1
Words: 2,834
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29257068
Author URL: https://archiveofourown.org/users/FullOfBoredom/pseuds/FullOfBoredom
Summary: There wasn’t a way to save him and everyone else. He could save the four loyal and himself, but every option for Cross was a trade, a head for a head.Time was running short, the echo of Dream’s terrified scream just now vocalized to his ears, the crescent arc of paint inching closer in his time slowed mind. There was none amongst those trapped behind him that deserved to die for Cross.If anyone did, it’d be his foolish brother for bringing this situation into being.When he glanced over one last time, the final time before Cross would become dust, a light tremor shaking Cross’s unstuck skull, he saw the hint of a purple tear and made the choice.A head for a head.
Relationships: Sans/Sans (Undertale)
Comments: 21
Kudos: 110





	Trade

The battle had gone on too long.

Nightmare hadn’t felt this tired since he recruited Dust and that had been eons ago now. The Star Sanses had combined forces to the point of locking down several of his gang, many immobile under layers of hardening paint, laced with something crafty he couldn’t quite place but had his brother’s magic all over it.

The real tipping point was Cross. Nightmare deflected another of his attacks aimed straight for Horror’s back. Apparently his brother found a weak link to turn into a mole, Cross glaring at his face with barely concealed anger.

Normally, with his entire team (Horror, Error, Dust, Killer, Cross), the pitiful few Stars had no way to overturn them. But the treachery evened the odds.

Nightmare kept out of Dream’s reach, attempting to dodge the arrows but finding it hard while his corruption dragged him down. It felt like a physical weight when he was weakened, and his body was struggling to stand, only held up by his own pride. Dream rarely focused on him. They weren’t an even match most of the time, but today had just been one skirmish too many.

“Boss!”

Horror had been locked down, joining Dust in being stuck in the thick oozing paint up to his chest. It dried like globs of hot glue, instant and thick, and wholy painful. 

It meant one more free opponent for the Stars and Nightmare had already started to think of the exit strategy.

“Fuck, Boss! Can I get a tentacle over here?” Killer growled as he repeatedly leapt back out of the painter’s range, Ink swiping his brush ferociously after him until he ran right into Error, who’d been too focused on Blue to pay attention.

Error glitched out with Killer stuck directly to him in their mess of paint, unable to reboot and free himself while forcibly touching the other, and Killer’s knife hand had been soaked in the stuff to keep him from using any bit of give.

Just him then. The traitor had done it.

At least, that’s what he thought until Ink bound Cross up while he wasn’t looking.

“Hey! What are you doing?! I’m-” Ink’s eyelights vanished awhile ago, and he slapped a blob of paint right into his mouth, trapping his jaw open while he wiggled furiously. 

“Now, for the real show.” Ink smiled, sharp and wicked as he wound up his brush. The tip turned bright red, glowing hot, a torrent of heat that’d burn through anything until there was nothing left. Nightmare had only seen it once before.

“Ink! Not Cross!” Dream still had his bow trained on Nightmare, trying to yell over the directions, but Ink paid him no mind. The empty eyes didn’t even turn to face them as he spoke.

“He’s just as bad. I won’t give him mercy.”

The next minute passed so slowly, Nightmare wasn’t entirely sure he was bound to time anymore. Dream’s eyes had widened considerably, turning to yell to make Ink stop, but he had already started the spin to fling the paint across the field like the blade of a scythe. Nightmare’s eye traced the trajectory long before the first droplet left the brush. In his caution, he’d not seen the way that Ink had trapped them. 

From where he’d wound up, a single swing would decapitate them all.

Not himself, he’d been put off to the side, pulled by Dream out of the line of fire to let Ink round up the others without being stopped. He had already begun to move towards them, but the thought of Dream knowing Ink had planned to kill them all and not stopping it filled him with revulsion so fierce he was glad he wasn’t turned to look at his brother’s face. From the small flash of Blue’s shock, he’d been having a similar thought.

His body could move quickly when he forced it to, a flash of cyan magic skipping him forward into the path of the swing.

Nightmare had taken his place in front of Killer and Error. If he held up his tentacles, he could take the blow and save them. But that would come at the cost of the Horror and Dust.

Alternatively, he could sacrifice his tentacles to save all of them, taking part of the hit in his corruption. It’d hurt like a bitch, but they’d make it to the next step. And he was prepared, red paint splitting the air in a white hot line approaching with quickening speed.

His eye flicked over to Cross.

Cross had resigned himself. Eyes closed, he faced death again with unsurprising expectation. He’d never made a secret of his distaste of Nightmare and his methods, his crew, but he clearly hadn’t hated him enough to not follow through on commands. He’d still done as he was told. What a good soldier, listening to orders and marching into death once again.

There wasn’t a way to save him and everyone else. He could save the four loyal and himself, but every option for Cross was a trade, a head for a head. 

Time was running short, the echo of Dream’s terrified scream just now vocalized to his ears, the crescent arc of paint inching closer in his time slowed mind. There was none amongst those trapped behind him that deserved to die for Cross. 

If anyone did, it’d be his foolish brother for bringing this situation into being.

When he glanced over one last time, the final time before Cross would become dust, a light tremor shaking Cross’s unstuck skull, he saw the hint of a purple tear and made the choice.

A head for a head.

The battlefield echoed with a loud squelch.

“BOSS!” Killer fought violently against the rapidly loosening paint. Some of the red had gotten through to melt away the prison, but that wasn’t the bigger concern. Around him, he could hear all of them struggling, finding a second wind to try and reach the body on the floor.

Nightmare had taken the entire swing directly. No deflection, no dodging, no protection. Just eaten the hit full on to save them all. And now, he’d collapsed, instantly down.

The red had burnt out in the corruption shortly after, but  _ Nightmare was melting. _

Black goop sloughed off the bones, thicker than blood and dark as pitch. Taking the hit for all five of them had left him entirely unguarded. Even Ink had paused at the sight.

“He...took it?” Dream’s soft confusion held his team in place. “I thought…”

Dust and Horror had freed themselves, as had Cross, while Error’s body misbehaved but was starting to gain traction. They flocked to their boss’s side, turning with renewed vigor to block him off from the Stars. Cross was frozen in a wide eyed stare.

“Fuck!” Killer attempted to pull Nightmare up by his tentacles, but they collapsed and detached instantly. Even the bones were hard to grab, the thick sludge stinging as it flowed off far in excess of his body’s size. “Holy shit, it’s never been this bad.” The cyan magic was dulling, faintly dying with its owner to not even smoulders. Even with the genuine negative feelings pouring off the group, Nightmare only got worse.

With a decisive stride, Cross took his place in front of Nightmare, his back to Killer and the others.

“Killer, take him and run. It has to be you, Dust and Horror can’t be left alone for too long, and Error can’t carry him.” He pulled his blade out to the Stars. “We’ll cover you and escape afterwards.”

“Where the fuck could I even go?!” He heard the whirl of a portal opening behind him, Error still blinded by pixels and glitching, but holding up his arm.

“Go KiLlEr. We HaVe ThIs CoVeReD.” He fought to stand, hand bracing his knee for leverage. “ThInK oF nIgHtMaRe.”

Killer’s face turned hard, gritting his teeth to dig through the stinging swamp to pull Nightmare into his chest, careful to support his neck, staining his entire hoodie in the dark liquid pouring off of Night’s body. Killer’s arms shook hard but clutched his small charge tight.

“Don’t die assholes.” Then he jumped through the portal.

Crossing over the boundary, it led to two other portals, and leaping through one of those led to another choice. Error had given him a random path of four to give them a chance to lose any possible tails. Killer couldn’t ruminate on the snap foresight however, Night’s body shaking violently, his head strangely wobbly. Killer sprinted to the nearest home, abandoned at the edge of Snowdin, desperate to get out of the cold of the winter wonderland.

“Fuck fuck fuck fuck fuck!” He kicked the door off its hinges. The dirty shack had a flat dusty table, barely big enough to hold Nightmare but Killer could feel Night’s body getting lighter in his arms.

He swiped his ruined hoodie arms over the table to remove the layer of filth before gingerly laying down Nightmare’s limp form.

“Boss!” His hands worriedly hovered, freezing over the spots of ivory poking through the pools of sludge, finally running dry after drenching everything in its wake. Night’s head laid awkwardly, sitting oddly since taking the attack. Killer belatedly realized that it might not be connected anymore.

“Holy shit. Fuck, I can’t heal for shit. Oh fuck.”

His hands fumbled over the delicate vertebrae, pulling it towards the neck stump. The goop kept it bound together by magic, but the corruption was fading fast, Night’s ankles already white and clean. The purity was climbing, inch by inch.

“Focus! Alright. What did he try to teach you?” 

His hand grasped around the break, holding the bones in place.

“It’s all about intent.” Killer’s magic was low and worn from the previous battle. He pointedly ignored the cleanliness spreading over Night’s chest.

“I want to save him.” He pushed the magic into his hands, not feeling it catch. It coated but didn’t penetrate into the bones. “Please just fucking save him.” They heated, but it still didn’t weave the stumps together. “Don’t let him die!” The sludge had cleared up through half of Night’s arms, Killer’s magic weakly touching the wound, but not progressing near fast enough. 

“Let me do this one god damn fucking thing right. I know I’m a fuck up, I know I’m built for killing not healin’.” His fingers held Night’s magic together in their fiery grip. “I know what I’m meant for, but they’re all relying on me.” His soul flickered into an inverted heart. “Nightmare’s relying on me.” 

The click of connection eased his trembling, forging ahead until the neck was fully together.

Killer crumpled the instant he removed his hands.

He gasped in air on the floor. It’d been a non-stop adrenaline ride for so long, from one almost death to another. His still soaked hoody clung to his ribs. His arms and chest stung with the goop burns that fizzled away sometime during the healing frenzy, bones still charred but the irritant fading with the source. With great effort, he raised his head above the table top to check on Nightmare.

Fully uncorrupted. A deep line was etched along the break, neck weak but together after the hasty patch job, otherwise a plain skeleton body covered in old breaks and scars, drowned in the loose sweater and shorts of Night’s normal apparel.

“How the hell?” He traced over the rampant cracks over Night’s skull, focused on the right side over where his dead eye used to be. Each scar was odd, only lined into the bone, healed evenly with no mismatched ends or irritation, but clearly broken many times. Night’s corruption must’ve held his body together under all that protection. Using his tentacles to tank hits made more sense now, his own body still breakable and thus painful. Killer scrambled to his knees to begin checking all over. Night could’ve taken a hit before the final that his corruption was hiding.

During his invasive exam, Night hadn’t stirred once. His chest barely rose, Killer having to lay a hand on it to feel the difference, the weight of his hand alone making it weaker.

“You better not kill me for this.” He shoved his arm deep into Night’s thoracic cavity, pulling out the dark apple soul carefully. He almost hadn’t found it with that pitiful energy level.

It didn’t have the magic to hover outside of Night’s body, sitting in Killer’s palm quietly. 

“I’ve seen lots of monsters fall down.” He confessed. “You’re about as weak as any of them right now. I just gotta hope you’re made of tougher stuff I guess.” He pushed a light pulse of magic through the apple, finding a shred of promise in the weak echo back in his hands. 

He turned his head to the still open door, chill whisked in with the wind, Killer shifting gears to the more immediate concerns.

“Shit, well now starts the “on the run” part of the adventure I guess.” They’d be found and moved by Error eventually, but he’d have to blend and provide until then. First thing was to explore the house he was squatting in to see if any of it was still up to keeping out the cold with few adjustments. He needed to leave Nightmare in a condition where he wouldn’t dust while Killer gathered supplies.

Unfortunately, the only room up to the task was a walk-in closet on the second floor. All the other rooms crumbled walls and window seals wouldn’t hold up to the snowy weather.

Tearing apart the house gave Killer some linens to work with, shaking out the gathering dust to create a makeshift nest in the closet. He wrapped up Nightmare’s body, supported his head, and closed the door, pushing a towel along the bottom to seal in as much warmth as possible.

Stealing clothes from the locals was a breeze, plucking off hanging lines but with odd additions to make it look like the wind took them. Food was equally easy though he was more discerning in what he took. Leaving a trail of missing shit was the fastest way to get caught. He tried to take things that no one was actively using, stuff no one would notice for days and definitely not at the same time. Covering snow tracks wasn’t the easiest, but he put in the effort to hide their little getaway from prying eyes. He walked directly up into the second floor and seated himself within the closet with Night. He still hadn’t moved from where Killer tucked him in earlier.

“Heavy sleeper today? Usually you’d be up yelling at me by now to get shit done.” Killer pulled clothes out of the bag. “I’ve already changed, but you gotta get out of those gross melted clothes.”

Killer unwound the linens around Night’s body. It looked so frail now, nothing like the imposing figure of his boss. He hesitated to even touch him, so pale and lifeless, face soft and lax in its disuse, Killer’s fingers trailed over the smooth cheekbones before he shook himself out of it. He had a job to do and it wasn’t molest Nightmare.

“Please don’t wake up during this fucking part…”

He slid the pants off, replacing them quickly with the new set quickly, sliding on the warm socks he’d found by the shopkeeper’s window for good measure. Wiping off his skull, he thought the hard part was over. 

“Thank the stars man. Alright, let’s finish this up. I even got you a sweater-” He’d pulled off Night’s ruined hoodie, tossing it off to the side, about to put on the next piece when he caught sight of the arms.

Littered with tiny horizontal scars. Too even and repetitive to be breaks.

“You, of all people?” He held one slender arm, sliding down, frowning the whole time. “Immortal god that you are, guess no one’s immune to peer pressure.”

Silence besides the ruffling of the new outfit, Killer rewrapped Nightmare into a cocoon of blankets before leaning back. Honestly, all he felt was run down. It’d been a really,  _ really, _ long day, and all he had was Nightmare’s unconscious body to show for it. How were the others? Would Night wake up? How long would they need to hide? Why did he have those scars? Lots of questions, no answers. His curiosity would have to be sated with the reality of being alive and nothing else for now.

Killer kicked off his shoes. Nothing to do but sleep off the stress, and there was only one place with blankets. Sliding under the stolen comforters, he pulled Night’s weak body up to his chest with a flush. He hadn’t slept with someone fully clothed in ages.

Adjusting his hold, Killer settled into the misshapen nest of fabric for the first of what would probably be many nights, whispering to Night’s still back.

“Don’t dust without me, alright?”

**Author's Note:**

> So...I'm going to try and finish a chaptered work. Pray for me. x.x


End file.
